International Journal of Trend in Scientific Research and Development (IJTSRD) Volume 3 Issue 5, August 2019 Available Online: www.ijtsrd.com e-ISSN: 2456 – 6470
Design Calculation of 40 MW Francis Turbine (Runner) Kyi Pyar Oo, Khaing Zar Nyunt, Ei Cho Cho Theik Department of Mechanical Engineering, Technological University, Toungoo, Myanmar
How to cite this paper: Kyi Pyar Oo | ABSTRACT Khaing Zar Nyunt | Ei Cho Cho Theik A water turbine is one of the most important parts to generate electricity in "Design Calculation hydroelectric power plants. The generation of hydroelectric power is relatively of 40 MW Francis cheaper than the power generated by other sources. There are various types of Turbine (Runner)" turbines such as Pelton Turbine, Cross-flow Turbine, and Francis Turbine Published in which are being used in Myanmar. International
Journal of Trend in In this paper, one of the hydroelectric power plant which is used Vertical Scientific Research IJTSRD26412 Francis Turbine type. The Francis turbine is one of the powerful turbine types. and Development Francis Turbine is a type of water turbine that was developed by James (ijtsrd), ISSN: 2456-6470, Volume-3 | Bicheno Francis. Hydroelectric Power Plant, Thaukyegat No.2, is selected to Issue-5, August 2019, pp.635-639, design the runner. This Vertical Francis Turbine is designed to produce 40 MW https://doi.org/10.31142/ijtsrd26412 electric powers from the head of 65 m and flow rate of 70.10m3/s. The design
parameters of 40 MW Vertical Francis Turbine runner’s diameter, height, Copyright © 2019 by author(s) and elevation, shaft, numbers of blades and blade angles are calculated. The initial International Journal of Trend in Scientific value of turbine output is assumed as 94%. The number of guide blades and Research and Development Journal. This runner blades are also assumed. The detailed design calculations of the runner is an Open Access are carried out. Moreover, the selection of the turbine type according to the article distributed head, the flow rate and the power are also performed. under the terms of the Creative Commons Attribution License (CC BY 4.0) KEYWORDS: Hydropower plant, Francis turbine, Head, Blade (http://creativecommons.org/licenses/by /4.0) I. INTRODUCTION Francis Turbines are almost mounted water from the shaft turbine. It must be assumed that friction is neglected and vertical to isolate water from the generator. Hydropower, fluid has the guidance through the turbine. That is, the also known as hydroelectric power, is a reliable, domestic, infinite number of vanes and relative velocity of the fluid is emission-free resource that is renewable through the always tangent to the vane. hydrologic cycle and hardness the nature energy of flowing water to provide clean, fast and flexible electricity. It is a A. Hydropower Plants clean form of power generation. Water is a natural source of A Hydropower Plant requires no fuel and it is much simpler energy to produce electricity. Water flowing under pressure to operate and maintain. Therefore the operating costs of the has to forms of energy: kinetic energy and potential energy. Hydropower Plant are much less than a thermal power plant. The water or hydraulic turbines convert this kinetic and Hydropower plants can be classified by many different potential energy into mechanical power. Hydraulic turbine aspects. This classification is according to the working of runners can only be performed by numerical methods due to hydropower plants, for example, they can by classified be the the complexity of these structures. The flow in hydraulic source of the water itself and by their construction or their turbines of the Francis type is quite complicated due to its turbine. Water power is one of the major sources of energy. three-dimensional nature and the curvature of the passages The other sources of energy being developed by water between runner blades. power are one of the major sources of energy. The other sources of energy being developed by fuels such as coal, oil, II. Design Consideration of Francis Turbine etc., and nuclear power are used for energy. These are some The expression for the power delivered to the shaft by of the conventional sources of energy. passing water is the same for all type of reaction turbines. In this case, it is necessary to use velocity diameter and B. Classification of Hydropower Plants moment of momentum equation (Euler’s Equation) to There are several classifications of related to the dimension calculate the power and efficiency of the inward flow of Hydropower Plants. Hydropower Plants can be classified turbine. It must be assumed that friction is neglected and into the following fluid has the guidance through the turbine. That is the 1. Large Hydro: 100MW to 1000MW infinite number of vanes and relative velocity of the fluid. 2. Medium Hydro: 15MW to 100MW The expression for the power delivered to the shaft by 3. Small Hydro: 1MW to 15MW passing water is the same for all type of reaction turbines. In this case, it is necessary to use velocity diameter and 4. Mini Hydro: 100kW to 1MW moment of momentum equation (Euler’s Equation) to 5. Micro Hydro: 5kW to 100kW calculate the power and efficiency of the inward flow 6. Pico Hydro: Fewer Watt to 5kW
@ IJTSRD | Unique Paper ID – IJTSRD26412 | Volume – 3 | Issue – 5 | July - August 2019 Page 635 International Journal of Trend in Scientific Research and Development (IJTSRD) @ www.ijtsrd.com eISSN: 2456-6470 C. Types of Hydropower Plants Table1.Turbine Selection (Head-Output) There are different types of Hydro Power Plants based on Turbine Effective Power types of facilities for the generation of hydropower. Types Head(m) Output(kW) Construction of large Hydropower Plants is a practical and Horizontal Over 75 100 ~ 5000 economically viable proposition as the capital costs of a Shaft Pelton project can be reduced with such installations. Hydropower Vertical Shaft Over 200 Over 4000 Plants may be classified in different ways depending on the Pelton certain classification. They are Horizontal 17 ~ 300 400 ~ 5000 1. Reservoir or Storage Type Shaft Francis 2. Run-of-River Type Vertical Shaft 40 ~ 300 2000 ~ 20000 3. Pumped Storage Type Francis Cross Flow 7.5 ~ 100 50 ~ 1000 D. Main Components of Francis Turbine Kaplan 10 ~ 70 Over 100 Francis Turbines are the medium head type of hydraulic Conduit Type 5 ~ 20 Over 1000 turbines, having stationary (Spiral casing, Stay Vanes and Bulb Guide Vanes) and rotating component. There are several Package 5 ~ 18 150 ~ 4000 components of Francis Turbine. Type Bulb They are 1. Spiral casing Table2. Relation between Water Temperature and 2. Stay ring Standard Stream Pressure 3. Guide vanes Water Temperature Saturated Steam 4. Runner (C) Pressure (m) 5. Draft tube 0 0.05 6. Shaft 5 0.09 10 0.13 15 0.17 20 0.24
Table3. The relation between Elevation and Atmospheric Pressure Elevation(m) Pressure (Atm) 0 10.33 100 10.21 200 10.09 300 9.97 400 9.35 500 9.73 600 9.52 700 9.50 Figure1. Francis Turbines 800 9.39
900 9.27 III. Design Theory of Francis Turbine 1000 9.16 Francis Turbines can be arranged in two ways; with vertical shaft and horizontal shaft. The vertical shaft arrangement 1100 9.05 requires the minimum space for installation and therefore 1200 8.94 permits the smallest area powerhouse. A. The efficiency of Francis Turbine It is not only more economical in space, but in many cases, it The expression for the power delivered to the shaft by is the only practical solution for large machines, especially passing water is the same for all type of reaction turbines. In when the topographical nature of the site limits the size of this case, it is necessary to use velocity diameter and the powerhouse. moment of momentum equation (Euler’s Equation) to calculate the power and efficiency of the inward flow By setting of the turbine is meant the location with respect to turbine. As an assumption, it must be assumed that friction is the head and tailwater level. Referring to Figure3.4 and neglected and fluid has the guidance through the turbine. equating the energies of flow at the exit end of the runner to That is, the infinite number of vanes and relative velocity of the energy of flow at the exit end of the draft tube. The result the fluid is always tangent to the vane, Steady and one- of the various condition of head, speed and capacity are that dimensional flow concept is used for calculation. runner of low speed and capacity are generally demanded P = Elemental mass x Tangential velocity d V cosα r under the high head, while runner of high speed and capacity P = m 1 1 1 are necessary under the low head. Similarly, T d V cosα r 2 = m 2 1 2 T m = dm (V2cosα1r1)r2 T t = m(V1cosα1r1 V2coscosα2r2 )
@ IJTSRD | Unique Paper ID – IJTSRD26412 | Volume – 3 | Issue – 5 | July - August 2019 Page 636 International Journal of Trend in Scientific Research and Development (IJTSRD) @ www.ijtsrd.com eISSN: 2456-6470 Power equation is A. Low-Speed Runner Power = Torque Angular Velocity B. Medium Speed Runner m(V cosα r V cosα r )ω C. High-Speed Runner Power = 1 1 1 2 2 2 D. High Speed- High Capacity Runner V &V cosα V V1cos α1 = w1 2 2 w2 U r ω & U r ω C. The setting of Turbine Draft Head 1 = 1 1 2 2 2 By setting of the turbine is meant the location with respect to
From above the relations, the equation of power is the head and tailwater level. Referring to and equating the m(V U ) energies of flow at the exit end of Power = w1 1 the runner to the energy of flow at the exit end of the draft Above equation can be changed by tube. UV P V 2 P V2 w1 2 2 Z Hs a f Z H η gH 1 m = d W 2g = W 2g Where, Where, h is hydraulic efficiency of turbine. B.P H1 = Energy lost in friction during the passage of water W UV through the draft tube g w1 h = H 1 = Elevation of existing of the runner through the draft Further the overall efficiency is, tube η Z = height of runner bottom above any assumed datum 0 = ηm ηh P2 =Pressure of exit section of runner B.P U1Vw1 Pa = Atmospheric pressure W gH UV d η g w1 0 = Since the flow through the draft tube is turbulent, the friction B.P 2 η WH V2 0 = d in the draft tube is proportional to . Also, velocities at the γ.Q various section of the draft tube are proportional to V2 since W = the profile of flow is fixed. B.P Thus, η0 γQHd = 2 p 2 Pa V2 Hs (1 K) Where, W = W 2g B.P = Power of the turbine in kW Where, η 2 0 V2 =Overall efficiency H1 ( ) 3 2g Q = Flow rate through the turbine in m /sec 2 V 3 ( 2 ) λ = Specific weight of water in kN/ m K = 2g H d = Design head in m η d = efficiency of the draft tube
V2 B. Runner Design as Affected by Speed and Capacity H H η 2 H a s d Head and available rate of flow varies widely among power 2 = 2g plant. Generally, large flow rates accompany with low head relatively small rates of flow are available at high heads. Where, Because of the difference in flow rates, low head usually σ = Thoma’s cavitation coefficient requires runner of large water capacity and high head required runner of low capacity. Accordingly, the runner may be again classified as being of high, low and medium capacity, and the term may refer to either the discharge rate or the power output since the latter is a function of the discharge.
Figure3. Static Draft Head and Various Type of Turbines
D. Specific Speed Limit of Specific Speed, 21000 Nsl 35 H 25 Calculate Specific Speed, after decided the rated speed, Figure2. Types of Runner Specific Speed,
@ IJTSRD | Unique Paper ID – IJTSRD26412 | Volume – 3 | Issue – 5 | July - August 2019 Page 637 International Journal of Trend in Scientific Research and Development (IJTSRD) @ www.ijtsrd.com eISSN: 2456-6470
1 2 IV. Result Data N = N Pt(i) s Table5. Result Data H 5 4 Descriptions Symbols Values Units Inlet tangential velocity U1 27.48 m/s E. Normal Efficiency Outlet tangential velocity U2 40.05 m/s N s N s η n = 1.172 ( ) 4.344 ( ) 82.321 Inlet absolute velocity V1 21.42 m/s 100 100 Outlet absolute velocity V2 5.61 m/s Maximum Efficiency,max= th 2.08log Pt(i) 4.61 Inlet flow velocity Vf1 10.95 m/s 2 Outlet flow velocity Vf2 5.61 m/s Speed factor, u= -4.4×(Ns/100) +0.039×(Ns/100)+0.695 1 Inlet whirl flow velocity Vw1 18.4 m/s H 2 Runner inlet diameter, D = Runner outlet Outlet whirl flow velocity Vw2 0 m/s 1 84.6×K u × N Inlet relative velocity Vr1 13.3 m/s diameter, Outlet relative velocity Vr2 40.41 m/s -2 2 D2= D1 ×[-1.7×12 (Ns/100) +0.44×(Ns/100)+0.321] Runner inlet angle α1 3075 Degree
Runner outlet angle α2 90 Degree Runner inlet height, Guide vane inlet angle β1 130 Degree B = D ×[8.7×10-3 (N /100)2 +0.15×(N /100)-0.028] 1 1 s s Guidae vane outlet angle β2 7.97 Degree
Runner outlet height, Turbine output power Pt 42.75 MW = 2 Generator Output power PG 42 MW B2 D2 ×[0.2875+0.0175×(Ns/100) ] Inlet diameter of Runner D1 2.1 m Runner shaft diameter, Outlet diameter of Runner D2 3.1 m
Inlet high of Runner B1 0.97 m = Pt Ds 2× (863 × N ) Outlet high of Runner B2 1.3 m Runner discharge diameter D3 3.22 m Inlet peripheral velocity, Runner shaft diameter Ds 0.8 m = πD 1 N U1 No: of Runner blades Z 16 60 No: of guide blades - 24 Inlet absolute velocity, Runner elevation Hs -6 m V = Turbine speed N 250 rpm 1 0.6 2gH Specific speed Ns 280 m-kW
Inlet flow velocity, Runaway speed Nr 486 rpm Q Critical speed Nc 972 rpm Vf1 = Efficiency t 94 % πD1 B1
Outlet peripheral velocity, Table 6.Comparison of Theory and Actual Data
πD 2 N Descriptions Theory Actual Units U 2 = 60 Runaway Speed 486.4 432.8 rpm
Runner inlet angle, Turbine of Power 42.7 41.24 MW
Vf1 Outlet Runner Diameter 3.06 2.94 m tan α = 1 Generation Power 41.89 40 MW Vw1 Runner Discharge Diameter 3.22 3.04 m Guide vane inlet angle, Shaft Diameter 0.8 0.7 m B = 180°-β1 1 Runner Outlet Height 1.3 1 m V tan β = f1 U1 Vw1
Theoretical Output Power, = Ptheo ρgQH
F. Design Input Data The required design data must be known from Thautyegat No.2 Hydroelectric Power Plant, in Bago Division (Myanmar).
Table4 .Input Data Descriptions Symbols Value Unit Effective Head H 65 m Discharge Q 70.10 m3/s
Overall efficiency ηo 94 % Output Power of Turbine P 44.7 kW Figure4. Two Dimensional View of Runner
@ IJTSRD | Unique Paper ID – IJTSRD26412 | Volume – 3 | Issue – 5 | July - August 2019 Page 638 International Journal of Trend in Scientific Research and Development (IJTSRD) @ www.ijtsrd.com eISSN: 2456-6470 The runner design is very important for any type of turbine. In this paper, the design calculation of the runner of 40 MW Vertical Francis Turbine which is taken from Thaukyegat No.2 Hydroelectric Power Plant is carried out. This runner is designed in the maximum power output conditions. Any type of turbine, runner blade design is very important. In this paper, the runner blade design of 40MW Francis Turbine is calculated.
Acknowledgment Firstly, the author would like to thank my parents for their best wish to join the B.E course at TU(Meiktila). The author greatly expresses her thanks to all persons who will concern to support in preparing this paper.
REFERENCES [1] Salman Bahrami, Multi-Fideidy, Design Optimization of Figure5. Three Dimensional View of Runner Francis Runner Blades, (Dec 2015)
Discussions and Conclusions [2] Einar Agnalt, Pressure measurements inside a Francis Hydropower is contained of two main portions as the Turbine Runner, (Oct 2014) mechanical and electrical system. Generally, Francis [3] Kurosawa, Design Optimization Method for Francis Turbines are placed in Vertical Francis Turbines Turbine, (Dec 2014) configuration. Vertical Francis Turbine is very widely used in the world for large hydroelectric Power plant. [4] Tun Oke, U, Design and Calculation of Francis Turbine (Runner), (Sept 2009)
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